Array antenna technology may not be extensively used in the licensed commercial microwave point-to-point or point-to-multipoint market, where more stringent electromagnetic radiation envelope characteristics consistent with efficient spectrum management may be more common. While antenna solutions derived from traditional reflector antenna configurations, such as prime focus fed axi-symmetric geometries, can provide high levels of antenna directivity and gain at relatively low cost, the extensive structure of a reflector dish and associated feed may require enhanced support structure to withstand wind loads, which may increase overall costs. Further, the increased size of reflector antenna assemblies and the support structure required may be viewed as a visual blight.
Array antennas typically utilize printed circuit technology or waveguide technology. The components of the array that interface with free-space, also referred to as the elements, typically utilize microstrip geometries, such as patches, dipoles, and/or slots, or waveguide components such as horns and/or slots. For example, flat panel arrays may be formed using printed slot or waveguide arrays in resonant or travelling wave configurations. The various elements may be interconnected by a feed network, so that the resulting electromagnetic radiation characteristics of the antenna can conform to desired characteristics, such as the antenna beam pointing direction, directivity, and/or sidelobe distribution. The various elements of such array antennas must also be protected from the environment, typically using an antenna enclosure. However, in some instances the antenna enclosure may negatively affect desired electromagnetic characteristics.